Quartz lamp assembly



Dec. 28, 1948. R. R. DAVIS 2,457,353

QUARTZ LAMP ASSEMBLY Filed July 30, 1945 IN VEN TOR. Q Rmwo/vo R. pawsHTTORNEY Patented Dec. 28, 1948 QUARTZ LAMPASSEMBLY Raymond E. Davis,Rochester, N. Y., asslgnor to i-Paragon Revolute Corporation,

Rochester,

N. Y., a corporation of New York Application July 30, 1945, Serial No.607,867

3 Claims. (Cl. 176-122) i This invention relates tea light source foruse in machines utilized for the exposure of photosensitive sheets.

In machines of this k nd and particularly in machines of the typeillustrated in the Sullivan Patent 2,093,785, the photosensitive sheetor paper to be exposed, travels around a rotating cylinder of Pyrexglass having therein a light source extending along its principal axis.This light source in certain machines is preferably in the form of ahigh pressure mercury quartz lamp. Such a lamp generates harmfulultraviolet light waves and also generates considerable heat which,unless dissipated or diverted tends to shorten the life of the lamp.

The main feature of the present invention relates to a novel quartz lampassembly in which the lamp is mounted within a transparent enclosure insuch a manner as to filter out harmful ultraviolet light waves and insuch a manner as not to shorten the life of the lamp.

Another feature of the invention relates to the novel arrangement formounting of a quartz lamp within a transparent enclosure.

These features and others will appear from the detailed description andclaims when taken with the drawing in which the single view is a sideelevation of the lamp assembly of the present invention with partsthereof broken away.

In the drawing, the numeral 5 designates a cylindrical quartz tube of ahigh pressure mercury quartz lamp. This tube terminates at each end in avacuum seal 6 through each of which seals there extends axially, astarting electrode 7, only the left end electrode being shown. The tubeafter being carefully evacuated is filled with a starting gas such asargon and with a few mercury droplets. Each electrode is connected to aninsulated conductor 8, which conductors are connectable to a suitableelectrical energizing source. Each end of the tube is provided with anend cap 9 provided with a peripheral flange 9a.

The quartz lamp is supported coaxially within a cylindrical Pyrex glassenvelope it which is open at each of its flared ends. The Pyrex glassenveloped is provided primarily to assure the proper operatingtemperature for the quartz lamp since it has been found that with suchproper operating temperature, the life of the lamp is greatly prolonged.The glass envelope also serves to confine objectionable ozone fumessince Pyrex glass, while it is highly transmittent to long ultravioletrays important to printing, completely absorbs the short ultra-violetwaves which generate ozone from the air.

The lamp at each of its ends is supported within the enveloped by a setof annular supports ll of mica or the like, the center openings throughwhich are of a size to receive the end cap 9 mounted on the end of thequartz lamp. The diameters of these supports are such that they engagethe inner surface of the envelope it.

Each end of the envelope is closed by a Pyrex glass end cover comprisinga head it and a reduced .neck it. The neck i5 is of such length that themica supports it and washer it are snugly held against the flange 9a. onthe cap when the head M of the cover engages its related flared end ofthe envelope. Each head is provided with a ventilating hole l6 and withan aperture ll. Insulating beads It with suitable asbestos string l9close the aperture ll, and provide protective insulation for eachconductor 8.

Each end cover is held in place by clamping means. This clamping meanscomprises a split ring 20 embracing a flared end of the envelope. Thering is provided with diametrically loc'ated ears 2i, each of which haspivotally supported thereon, a metal strip 22 shaped to extend over thehead it where the perforated free ends of the adjacent pair of strips,receive a bolt 23 to clamp the strips together.

The lamp assembly is preferably mounted within the printing machine onspaced brackets 24.

The assembly of the present invention provides an arrangement wherein aglass envelope filters out the harmful short ultraviolet light wavesgenerated by the quartz lamp and wherein the lamp is supported in a wayto greatly prolong the life thereof.

What I claim is:

i. In a quartz lamp assembly, a lamp comprising a closed quartz tubehaving an ionizible medium therein, each end of said tube being providedwith a vacuum seal having an electrode sealed therein to project intothe tube, a conductor connected to each electrode externally of saidtube, a shield comprising a cylinder of material having the property ofpassing long ultraviolet rays therethrough and of preventing the passagetherethrough of short ultraviolet rays such as generate ozone from theair, said cylinder being open at both of its ends, said shield alsocomprising removable ventilating covers closing the open ends of saidcylinder, and mica-like supporting means engaging the inner surface ofeach end of the cylinder, said supporting means also engaging each endof the tube.

2. In a quartz lamp assembly, a lamp comprising a closed quartz tubehaving an ionizible meproperty of passing long ultraviolet raysthereductor connected to each electrode externally oi said tube, ashield comprising a cylinder of material having the property of passinglong ultraviolet rays therethrough and of preventing the passagetherethrough of short ultraviolet rays such as generate ozone from theair,said cylinder being open at both of its ends, said shield alsocomprising covers having necks fitting into the respective open ends 01said cylinder to close the same, and supporting means having theperiphery thereof engaging each end of the cylinder, said supportingmeans being held in position by the respective ends of said covers andengaging the periphery of each end of the tube.

3. In a quartz lamp assembly, a lampvcomprising a closed quartz tubehaving an ionizable medium therein, each end oi said tube being providedwith a vacuum seal having an electrode sealed therein to project intothe tube, a conductor connected to each electrode externally of saidtube, a flange cap carried by the tube and encircling each electrodeadjacent its seal, a shield comprising a cylinder of material having thethrough and oi preventing the passage therethrough of short ultravioletrays such as generate ozone from the air, said cylinder being open atboth 'of its ends, said shield also comprising covers having necksfitting into the respective open ends of said cylinder to close thesame, and supporting means having portions thereof engaging each end orthe cylinder, said supporting means engaging portions of each end of thetube and being held by the respective ends ofsaid covers and by therespective flanges.

RAYMOND R. DAVIS.

REFERENCES CITED The following references are of record in the me ofthis patent:

UNITED STATES PATENTS

